Photomask mounting/housing device and resist inspection method and resist inspection apparatus using same

ABSTRACT

A resist inspection apparatus is provided which has a configuration in which a reticle is separated from a pellicle. A reticle cassette is made up of two pieces of plate members. A hollowed portion with a shape allowing the reticle to be inserted into the plate member. Another hollowed portion having a shape being slightly larger than that of the resist of the reticle is formed on the plate member. In the circumference of the hollowed portion is placed a pellicle frame on which a protective film is formed in a stretched manner. In the concave portion is housed in the reticle with a resist on the reticle directed toward the hollowed portion. The reticle is put in sealed space.

REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.12/341,208 filed Dec. 22, 2008 and claims the benefit of its priority.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photomask mounting/housing device anda resist inspection method and resist inspection apparatus using thesame and more particularly to the photomask mounting/housing deviceconfigured so that a photomask can be easily separated from atranslucent protective member and the resist inspection method using thephotomask mounting/housing device and the resist inspection apparatushaving the photomask mounting/housing device.

2. Description of the Related Art

Conventionally, a photomask (reticle) is used to manufacturesemiconductor integrated circuits. Before the photomask is used formanufacturing semiconductor integrated circuits, an inspection isperformed to check whether a resist formed on a substrate of a photomaskhas an expected and predetermined pattern. Various types of technologieshave been developed for the inspection of resists. Examples of thesetechnologies are described below.

One example of the related resist inspection apparatus is shown in FIG.4. As shown in FIG. 4, in the related resist inspection apparatus, light31 for resist inspection is applied from one side of a reticle 2 and apattern image is formed based on reflected light fed through an opticalelement such as a lens 30 and a desired inspection is performed usingthe obtained pattern image itself or by comparison between the obtainedpattern image and a pattern image designed in advance. This example isdisclosed in Patent Reference 1 (Japanese Patent Application Laid-openNo. Hei06-020934).

Also, in another example of a related resist inspection apparatus whoserough configurations are the same as those shown in FIG. 4, the resistis inspected while air purging is performed on optical elements in thesame way as shown in FIG. 4. This example is disclosed, for example, inPatent Reference 2 (Japanese Patent Application Laid-open No.2006-245400).

Also, in still another example of a related resist inspection apparatus,as shown in FIG. 3, as a photomask to be used in the resist inspectionapparatus, a pellicle 3 is coupled to a reticle 2. This example isdisclosed in Patent Reference 3 (Japanese Patent Application Laid-openNo. 2003-315983).

Furthermore, in still another example of a related resist inspectionapparatus, a pellicle frame attached to a pattern surface of a photomaskis divided, by pin-coupling, into two portions, an upper frame and alower frame. This example is disclosed in Patent Reference 4 (JapanesePatent Application Laid-open No. Hei05-216214).

However, the above related technologies have the following problems.That is, in the case of the related resist apparatus disclosed in thePatent Reference 1, when the light 31 for inspection is applied to theresist 7 on the reticle 2, gas 20 is released from the resist 7, whichcauses the gas 20 to remain, as an adherent 21, on a surface of anoptical element such as the lens 30 (see FIG. 6). There is atechnological problem that, if the residual adherent 21 occurs at everytine of the inspection, the performance of the optical element of thelens 30 is degraded and finally the inspection becomes impossible. Acountermeasure against the degradation of the lens performance is towipe the adherent 21 off the lens 30, however, it is impossible to fullyrestore the performance of the lens 30 only by the wiping method and,therefore, unless the lens 30 is replaced, the continuation of theinspection is made impossible. Even in the case where the inspection isto be continued by replacing the lens 30, the lens 30 is expensive andits delivery time is long, thus causing costs to mount and much time tobe taken for the repairing process.

The residual adherent 21 caused by the gas presents further problems.That is, if the inspection is performed on another reticle 2 b in astate where the adherent 21 is being left, as shown in FIG. 7, theresidual adherent 21 causes a difference between a pattern image to beobtained from the inspection and a pattern image designed in advanceand, as a result, the difference in pattern is extracted, as a defect,together with an actual defect that may occur in the resist 7 b by theimage comparing device in the resist inspection apparatus.

If the above information only is used for the comparison, it is madeimpossible to differentiate between the defect caused by the residualadherent 21 and the actual defect of the resist 7 b. In order to achievethe exact differentiation, the further processes of inspection and/orchecking are required which include the method by the re-inspection withthe reticle 2 b rotated horizontally by 90, 180, or 270 degrees, etchingof the reticle 2 b, detailed checking of the lens 30, or the like.

Out of the above differentiation methods, the re-inspection method bythe rotation of the reticle 2 b presents a further problem, that is,during the re-inspection process, the adherent 21 is accumulated more,which possibly makes it more difficult to differentiate between thedefect caused by the residual adherent 21 and the actual defect of theresist 7 b. Also, in the case of the differentiation method by etchingthe reticle 2 b for checking, if an actual defect is found in the resist7 b, the use of the reticle 2 b becomes impossible. Furthermore, themethod by detailed checking of the lens 30 is practically impossible dueto its difficulty and time required for the checking process.

Various countermeasures against the degradation of performance ofoptical elements such as the lens 30 are available, however, a peculiartechnological problem still arises in each of the countermeasures.Therefore, the technological problem related to the degradation ofperformance of optical elements such as the lens 30 caused by gasremains unsolved. The technological problem related to the degradationof performance of optical elements is partially solved by the technologydisclosed in the Patent Reference 2.

However, there is the following technological problem in the abovetechnology using the air purge. In the technology disclosed in thePatent Reference 2, the air purging is performed on the optical elementto avoid the direct contact between the gas 20 and lens 30. However,unless the purging air is rectified smoothly to purge the lens 30, thefluctuation of inspection light 31 occurs, as a result, making itdifficult to obtain the uniformity of the light 31 which causesunevenness in image to show up and makes it impossible to perform theinspection itself. Furthermore, due to the attachment of the air purgingcomponent, difficulties exist in the maintenance of the apparatus.

The technological problem arises in the method disclosed in the PatentReference 3. That is, if the resist 7 on a photomask is to be inspectedby using the method, when the resist 7 is re-formed or etched after theinspection, it is necessary to take out the pellicle 3 or the pellicle 3together with the pellicle frame 8 from the reticle 2 and, therefore,during the process of the removal, the reticle 2 may be contaminated ordamaged.

The Patent Reference 4 discloses the configuration in which a photomaskis housed between the two pellicle frames being pin-coupled to eachother, thus requiring an upper frame and a lower frame. However, noconfiguration is suggested in which a photomask is housed in a pellicleframe to which a pellicle is attached in an stretched manner.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide a photomask mounting/housing device in which easy separationbetween a photomask and a translucent protective member is made possibleand a resist inspection method using the photomask mounting/housingdevice and a resist inspection apparatus having the photomaskmounting/housing device.

According to a first aspect of the present invention, there is provideda photomask mounting/housing device for receiving and housing aphotomask, including frame bodies each having a concave portion with ashape allowing the photomask to be received and housed and hollowedportions each formed in the concave portion with a shape allowing atleast a resist formed region of the photomask to be inserted, and atranslucent protective member disposed outside the hollowed portions ofthe frame bodies and forming sealed space so as to be opposite to and beapart from a resist.

According to a second aspect of the present invention, there is provideda resist inspection method for applying light to a photomask andinspecting a resist of the photomask by receiving reflected light fromthe photomask, including a step of housing the resist of the photomaskinto a concave portion of a photomask mounting/housing device havingframe bodies each having a concave portion with a shape allowing thephotomask to be received and housed and hollowed portions each formed inthe concave portion with a shape allowing at least a resist formedregion of the photomask to be inserted and a translucent protectivemember disposed outside the hollowed portions of the frame bodies andforming sealed space so as to be opposite to and be apart from a resist,with the resist of the photomask directed toward the translucentprotective member side and a step of applying light from the translucentprotective member side to perform inspection of the resist.

According to a third aspect of the present invention, there is provideda resist inspection apparatus for applying light from an optical systemto a photomask placed in a photomask placing portion and receivingreflected light from the photomask to perform inspection of a resist ofthe photomask, including a photomask mounting/housing device to beplaced in the photomask placing portion which has frame bodies eachhaving a concave portion with a shape allowing the photomask to bereceived and housed and hollowed portions each formed in the concaveportion with a shape allowing at least a resist formed region of thephotomask to be inserted and a translucent protective member disposedoutside the hollowed portions of the frame bodies and forming sealedspace so as to be opposite to and be apart from a resist and whichhouses, in its concave portion, resists of the photomask, via thehollowed portion, arranged so as to be directed toward the opticalsystem.

With the above configurations, it is made possible to obtain thedevice/method that can provide great advantages by separating thephotomask from the photomask mounting/housing device and also thatserves to achieve effects of preventing the release of gas out of thephotomask to maintain the performance of the optical system and ofavoiding the replacement of the optical system. Also, by configuring asabove, easy replacement of the photomask mounting/housing device andtranslucent protective film is made possible. Also, by configuring asabove, during an inspection of the photomask, no contamination and/ordamage of the photomask occurs and inspection processes can be reducedand inspection time can be shortened. Also, easy etching processes afterbeing inspected and easy recoating with resists can be made possible.Also, even when the resist inspection is performed on a plurality ofreticles, the optical elements are not affected by gas released from theresist. All that is needed to exclude an influence by the gas is to formthe sealed space between the photomask mounting/housing device andtranslucent protective film and no other device/method of various typesare required.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages, and features of the presentinvention will be more apparent from the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a diagram showing a reticle mounting/housing device accordingto a first exemplary embodiment of the present invention;

FIG. 2 is a diagram showing a resist inspection apparatus for a reticleaccording to a second exemplary embodiment of the present invention;

FIG. 3 is a diagram explaining a significance of the resist inspectionapparatus for the reticle according to the second exemplary embodimentof the present invention;

FIG. 4 is a diagram explaining a first related resist inspectionapparatus;

FIG. 5 is a diagram explaining configurations of a photomask used in asecond related resist inspection apparatus;

FIG. 6 is a diagram explaining one defect of the above related resistinspection apparatus; and

FIG. 7 is a diagram explaining another defect of the above relatedresist inspection apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS

Best modes of carrying out the present invention will be described infurther detail using various exemplary embodiments with reference to theaccompanying drawings. According to the present invention, a concaveportion is formed in a photomask mounting/housing device into which aphotomask is housed. Moreover, the photomask mounting/housing device inwhich the photomask is housed in its concave portion is used by a resistinspection apparatus.

First Exemplary Embodiment

FIG. 1 is a diagram showing a reticle mounting/housing device of thefirst exemplary embodiment of the present invention. In the reticlemounting/housing device 1 of the first exemplary embodiment, nomechanical and rigid coupling exists between a reticle 2 and pellicle 3connected to a reticle cassette 4. The reticle 2 is housed in a concaveportion formed in the reticle cassette 4 and the reticle cassette 4 isplaced in a resist inspection apparatus to be used for the inspection ofa resist coated on the reticle 2.

The reticle 2 is so configured that the resist 7 having a predeterminedpattern is coated on its translucent substrate 6. The translucentsubstrate 6 is made of, for example, glass, quartz, or the like. Thepellicle 3 is so configured that a barrier layer (protective film) 3 fmade of an ultra-thin metal film or the like is formed on one endportion 8 f of a pellicle frame 8 in a stretched manner. The pellicle 3is secured through another end portion 8 p of the pellicle frame 8 tothe reticle cassette 4 in a closely contacted state. The reticlecassette 4 is made up of two pieces of plate members (flat plates) 9 and10 closely contacted with each other. Each of the plate members 9 and 10is hollowed so as to have a predetermined shape. The plate member 9after being hollowed, as shown in FIG. 1, has a shape that allows thereticle 2 to be received and housed and, in general, being square inshape. The plate member 10 after being hollowed, as shown in FIG. 1, hasa shape that surrounds a circumference of the resist 7 coated on thereticle 2. As a result, a surface surrounding a hollowed portion 10 hformed in the plate member 10 making up the reticle cassette 4 serves asa mounting surface 10 p on which the reticle 2 to be inserted via ahollowed portion 9 h of the plate member 9 is put.

Sealed space is formed in a portion surrounded by a surface of thereticle 2, on which the resist is coated, placed on the mounting surface10 p in a closely contacted state via the hollowed portion 9 h of thereticle cassette 4 configured as above, by the plate member 10, pellicleframe 8, and protective film 3 f. The space is so formed as to have aninterval distance between the resist 7 coated on the reticle 2 and theprotective film 3 f being long enough to keep generated gas 20 trappedtherein. The distance is set within a range between, for example, 1 mmto 6 mm.

Next, by referring to FIG. 1, functions of the reticle mounting/housingdevice of the first exemplary embodiment are described. To the reticlecassette 4 is secured the other end portion 8 p of the pellicle frame 8in a closed contacted state and on one end portion 8 f of the pellicleframe 8 is attached the protective film 3 f in a stretched manner. Byinserting the reticle 2 into the hollowed portion 9 h of the reticlecassette 4 by a proper mounting means, for example, a vacuum-assisteddetachable means and by placing the reticle 2 on the mounting surface 10p of the reticle cassette 4 in a closed contacted state, the sealedspace can be formed on the surface of the reticle 2 on which the resistis formed. Thus, simply by placing the reticle 2 on the mounting surface10 p of the reticle cassette 4, that is, only by contact between theirsurfaces, the sealed space can be formed. Also, the sealed space can beremoved by setting the reticle 2 apart from the mounting surface 10 p,which provides a great advantage in handling the reticle 2.

Accordingly, by configuring as above, the release of the gas 20 producedfrom the resist 7 to the outside of the photomask can be prevented whenlight 31 is applied via a lens 30 to the resist 7. Here, reflected light32 is generated from the reticle 2 irradiated with the light 31.Moreover, the above configuration serves to prevent the degradation inperformance of optical elements such as the lens 30 and cleaning of thelens 30 becomes unnecessary. No replacement of the lens 30 requiringhigh costs and long delivery time is needed, thereby saving costs andtime greatly.

Thus, according to the configurations of the reticle mounting/housingdevice according to the first exemplary embodiment, by the separationbetween the reticle 2 and reticle cassette 4, a means having a greatadvantage can be provided and the release of the gas 20 to the outsideof the photomask 1 can be prevented, which serves to maintain theperformance of the optical system and to obtain effects by the avoidanceof replacement of the optical system.

Second Exemplary Embodiment

FIG. 2 is a diagram showing a resist inspection apparatus for a reticleof the second exemplary embodiment of the present invention. FIG. 3 is adiagram explaining a significance of the resist inspection apparatus fora reticle of the second exemplary embodiment. The configuration of theresist inspection apparatus of the second exemplary embodiment differsfrom that of the first exemplary embodiment in that she reticle cassetteemployed in the first exemplary embodiment is used for the resistinspection apparatus for the reticle. The resist inspection apparatus50, as shown in FIG. 2, chiefly includes a reticle cassette 4 placed ina placing portion in the resist inspection apparatus 50, a lens 30, animage processing device 40, a storage device 41, and an image comparingdevice 42. In the reticle cassette 4 is housed a reticle 2. Theconfigurations other than those of the reticle cassette 4 are the sameas those in the first exemplary embodiment and the same referencenumbers are assigned to the same components and their detaileddescriptions are omitted accordingly.

Next, by referring to FIGS. 2 and 3, operations of the resist inspectionapparatus 50 of the second exemplary embodiment are described. Prior toan inspection of a resist 7 coated on the reticle 2, a reticle cassette4 is placed on the placing portion of the resist inspection apparatus 50in which the reticle 2 is housed in a manner in which the resist 7 onthe reticle 2 is directed toward a pellicle 3. The reticle 2 is notmechanically coupled to the reticle cassette 4 and both are configuredto be freely contacted with or separated from each other. Therefore,when etching is to be performed without any defect or when the reticle 2is to be recoated with the resist 7, the process ofattachment/detachment of such the pellicle 3 as employed in the PatentReference 3 becomes unnecessary. As a result, contamination and/ordamage of the reticle 2 can be prevented, whereby the number of processsteps can be reduced and the process time can be shortened. Also, aneasiness of a replacement of the pellicle frame 8 and/or the pellicle 3can be achieved.

When the inspection of the resist 7 is started by the resist inspectionapparatus 50, light 31 for inspection is applied from an optical systemcontaining a lens 30 for capturing an image to a surface having theresist 7 coated on the reticle 2 through the protective film 3 f of thepellicle 3. The application of the light 31 causes gas 20 to be releasedfrom the resist 7. The released gas 20 is trapped in sealed space formedbetween the reticle cassette 4 and the reticle 2. Therefore, no gas 20is left as an adherent 21 (see FIG. 6) on an optical element such as thelens 30, whereby degradation in performance of the optical element suchas the lens 30 can be prevented.

The resist inspection can be performed in a state where the residualadherent 21 is prevented. When the inspection light 31 is applied to thesurface of the reticle 2 on which the resist has been coated, thereflected light 32 is produced which contains a pattern image of theresist 7 and the produced pattern image is processed by the imageprocessing device 40 and the processed pattern image is stored in thestorage device 41. By inputting the pattern image stored in the storagedevice 41 and a predesigned pattern image using the image comparingdevice 42, only an actual defect of the resist 7 can be extracted.

This can be realized owing to the following reason. That is, asdescribed above, when the inspecting light 31 is applied to the resist 7on the reticle 2, the gas 20 is released from the resist 7, however, thereleased gas 20 is trapped in the sealed space formed by the reticle 2,reticle cassette 4, and pellicle 3 and is not left as the adherent 21 onthe image capturing lens 30. Thus, since the gas 20 is not left as theadherent 21 on the image capturing lens 30 by configuring as above, evenwhen the inspection of an resist of another reticle 2 a set in thereticle cassette 4 (see FIG. 3) is performed by using the same resistinspection apparatus 50 used in the previous inspection, no adherent 21produced during the previous inspection is left on the lens 30 and,further, no adherent 21 is produced during the present inspection and,as a result, no degradation in performance of the lens 30 occurs andthere is no trouble in the resist inspection. That is, by using the sameresist inspection apparatus 50, it is made possible to sequentially andrepeatedly perform the inspection of a plurality of reticles 2. Asdescribed above, the reticle cassette 4 and reticle 2 are configured soas to be separated from each other, thereby enabling easy etchingperformed after being inspected and easy recoating with the resist 7.

The above sealed space is formed in the way described above and,therefore, the air purge configuration and sealed structure ofelectrical elements such as the lens 30 employed in the resistinspection apparatus disclosed in the Patent Reference 2 becomeunnecessary, whereby costs can be reduced and easiness of themaintenance can be achieved. Also, by using, as the material for thepellicle 3 forming the above sealed space, the gas barrier film such asan ultra-thin metal film, an anti-gas characteristic is enhanced.Moreover, in the case of the gas barrier film, costs for making thematerial ultra-thin can be reduced when compared with other materialssuch as, for example, glass or plastic. The term “ultra-thin” denotesthe thickness of several microns. This thickness is a value to bedetermined from a viewpoint of a possibility that a variation in opticalaberration to the light 31 for inspection occurring at a time of thereplacement of the pellicle 3 gets in the way of the inspection.

Though the gas 20 adheres to the pellicle 3, since the reticle cassette4 and/or pellicle 3 are so configured as to be easily replaced, byreplacing either or both of the reticle cassette 4 and pellicle 3, theproblem occurring in the Patent Reference 1 can be solved.

Thus, according to the second exemplary embodiment, the reticle 2 is notmechanically and rigidly coupled to the reticle cassette to which thepellicle is attached and the reticle 2 can be easily separated from thereticle cassette 4. The pellicle frame 8 and pellicle 3 can be easilyreplaced. Neither the contamination nor the damage of the reticle 2occurs during the inspection of the reticle 2 and, further, the numberof inspection process steps can be reduced and the required time for theinspection can be shortened. Moreover, since the reticle cassette 4 andreticle 2 are so configured as to be separated from each other, theetching after being inspected and recoating with the resist 7 can beeasily performed. Even when resists on a plurality of reticles 2 areinspected, the employed optical elements are not affected by the gasreleased from the resist 7. To avoid the influence of the gas, the onlything that is needed is a means to form the sealed space between thereticle cassette 4 and reticle 2, whereby other types of means are notrequired.

While the invention has been particularly shown and described withreference to exemplary embodiments thereof, the invention is not limitedto these exemplary embodiments. It will be understood by those ofordinary skill in the art that various changes in form and details maybe made therein without departing from the spirit and scope of thepresent invention as defined by the claims. For example, in the aboveexemplary embodiments, the reticle cassette 4 is made up of two piecesof the plate members 9 and 10, however, the reticle cassette 4 may beconfigured by forming a concave portion in a single member to form ahollowed portion at a bottom wall in the concave portion and to coverthe hollowed portion with the pellicle.

The photomask mounting/housing device and resist inspection method andresist inspection apparatus disclosed in the present invention can beapplied to a field such as an EUV (Extreme UltraViolet) mask and a maskhigh-definition mask for FPD (Flat Panel Display) in which their mastersare extremely expensive and costs for processing after a writing ofpatterns are high.

1. A photomask mounting/housing device for receiving and housing aphotomask comprising: a first frame body having a first hollowed portionwith a shape allowing said photomask to be received and housed; a secondframe body, coupled to said first frame body, in a combined manner, andhaving a second hollowed portion with a shape allowing at least a resistforming region of said photomask to be inserted, such that a concaveportion is formed between said first hollowed portion in said firstframe body and said second hollowed portion in said second frame body;and a translucent protective member disposed outside said secondhollowing portion in said second frame body to form sealed space so asto be opposite to and be apart from said resist.
 2. The photomaskmounting/housing device according to claim 1, wherein said translucentprotective member comprises a supporting body formed along an entirecircumference of said second hollowed portion and a translucentprotective film formed, in a stretched manner, along an entirecircumference of a free end of said supporting body.
 3. The photomaskmounting/housing device according to claim 1, wherein said first framebody is a flat plate and said second frame body is also a flat plate. 4.The photomask mounting/housing device according to claim 2, wherein saidtranslucent protective film is an ultra-thin metal film.
 5. Thephotomask mounting/housing device according to claim 2, wherein adistance between said resist and said translucent protective film isbetween 1 mm and 6 mm.
 6. A resist inspection method for applying lightto a photomask and inspecting a resist of said photomask by receivingreflected light from said photomask, comprising: a step of housing saidresist of said photomask into a concave portion of a photomaskmounting/housing device having a first frame body having a firsthollowed portion with a shape allowing said photomask to be received andhoused, and a second frame body, coupled to said first frame body, in acombined manner, and having a second hollowed portion allowing at leasta resist forming region of said photomask to be inserted, such that aconcave portion is formed between said first hollowed portion in saidfirst frame body and said second hollowed portion in said second framebody, and a translucent protective member disposed outside said secondhollowing portion in said second frame body to form sealed space so asto be opposite to and be apart from said resist, with said resist ofsaid photomask directed toward said translucent protective member side;and a step of applying light from said translucent protective memberside to perform inspection of said resist.
 7. The resist inspectionmethod according to claim 6, wherein said translucent protective membercomprises a supporting body formed along the entire circumference ofsaid second hollowed portion and a translucent protective film formed,in a stretched manner, along the entire circumference of a free end ofsaid supporting body.
 8. The resist inspection method according to claim6, wherein said first frame body is a flat plate and said second framebody is also a flat plate.
 9. The resist inspection method according toclaim 7, wherein said translucent protective film is an ultra-thin metalfilm.
 10. The resist inspection method according to claim 7, wherein adistance between said resist and said translucent protective film isbetween 1 mm and 6 mm.
 11. A resist inspection apparatus for applyinglight from an optical system to a photomask placed in a photomaskplacing portion and receiving reflected light from said photomask toperform inspection of a resist of said photomask, comprising: aphotomask mounting/housing device to be placed in said photomask placingportion which has a first frame body having a first hollowed portionwith a shape allowing said photomask to be received and housed, a secondframe body, coupled to said first frame body, in a combined manner, andhaving a second hollowed portion with a shape allowing at least a resistforming region of said photomask to be inserted, such that a concaveportion is formed between said first hollowed portion in first framebody and said second hollowed portion in second frame body, and atranslucent protective member disposed outside said second hollowingportion in said second frame body to form sealed space so as to beopposite to and be apart from said resist, and which houses, in saidconcave portion, said resist of said photomask, via said second hollowedportion, arranged so as to be directed toward said optical system. 12.The resist inspection apparatus according to claim 11, wherein saidtranslucent protective member comprises a supporting body formed alongthe entire circumference of said second hollowed portion and atranslucent protective film formed, in a stretched manner, along theentire circumference of a free end of said supporting body.
 13. Theresist inspection apparatus according to claim 11, wherein said firstframe body is a flat plate and said second frame body is also a flatplate.
 14. The resist inspection apparatus according to claim 12,wherein said translucent protective film is an ultra-thin metal film.15. The resist inspection apparatus according to claim 12, wherein adistance between said resist and said translucent protective film isbetween 1 mm and 6 mm.